What abiotic factors might account for differences in net primary productivity in ecosystems?

The factors in an ecosystem that are considered abiotic, or nonliving, are very important to the primary productivity of the ecosystem. Those factors are both chemical and physical, and include light (radiation), temperature, water, atmospheric gases, and soil. Climate generally influences all the abiotic factors. The ecosystems that are in and around the equator generally have the greatest primary productivity, because of the moisture and conducive temperature. All the major cycles , such as the nitrogen, carbon, and water, occur with higher regularity because there is more direct radiation from the sun at these locations. As you progress towards the poles, there is less direct radiation, so the degree of primary production starts to lessen. By the time you get to the ninety degrees, north and south, latitude marking, these areas receive the least amounts of direct radiation, causing a marked decrease in the amount of primay production.